Hearing instrument

Abstract

A hearing instrument microphone device incudes at least two microphone sound ports (or sound inlets), a pressure difference microphone in communication with at least two of the sound ports and a pressure microphone in communication with at least one of the sound ports, wherein the acoustic centers of the pressure difference microphone and the pressure microphone essentially coincide.

What is claimed is: 
     
       1. A hearing instrument including a signal processor, a receiver, and a microphone device, the microphone device comprising:
 at least two microphone ports, 
 a pressure difference microphone in communication with at least two of the ports, 
 a pressure microphone in communication with at least one of the ports and having an effective acoustic center, wherein the effective acoustic center of the pressure microphone is the center point of the ports that are in communication with the pressure microphone, 
 wherein the effective acoustic center of the pressure microphone is essentially at equal distances from locations of the ports in communication with the pressure difference microphone, and 
 wherein the signal processor comprises a first input channel and a second input channel, and is capable of
 obtaining a first digital input signal representative of an acoustic signal incident on the pressure microphone via the first input channel, and a second digital input signal representative of an acoustic signal incident on the pressure difference microphone via the second input channel, 
 processing the first and second digital input signals, 
 combining the first and second digital input signals into a processed signal with an adjustable directional dependency, and 
 activating the receiver to convert an electronic output signal produced by the signal processor into an acoustic output signal. 
 
 
     
     
       2. The hearing instrument according to  claim 1 , wherein the pressure microphone and the pressure difference microphone are arranged in a common casing. 
     
     
       3. The hearing instrument according to  claim 1 , wherein the pressure difference microphone comprise a pressure difference microphone cartridge with a membrane dividing the volume within the cartridge in two volume parts, the first volume part being, via a first opening of the pressure difference microphone, coupled to a first one of the ports, whereas the second volume part is, via a second opening of the pressure difference microphone, coupled to a second one of the ports. 
     
     
       4. The hearing instrument according to  claim 1 , wherein the pressure microphone is a pressure microphone comprising a pressure microphone cartridge, and a membrane dividing the cartridge volume in two volume parts, the first volume part being, via at least one pressure microphone opening, coupled to at least one of the ports, whereas the second volume part is closed. 
     
     
       5. The hearing instrument according to  claim 1 , wherein membranes of the pressure microphone and of the pressure difference microphone are parallel. 
     
     
       6. The hearing instrument according to  claim 1 , wherein the pressure difference microphone and the pressure microphone are both coupled to the same plurality of ports. 
     
     
       7. The hearing instrument according to  claim 1 , wherein the pressure difference microphone is coupled to two pressure difference microphone ports and wherein the pressure microphone is coupled to at least one pressure microphone port separate from the pressure difference microphone ports. 
     
     
       8. The hearing instrument according to  claim 1 , wherein the signal processor is capable of applying a correction filter to at least one of the first digital input signal and the second digital input signal, prior to combining the signals. 
     
     
       9. The hearing instrument according to  claim 1 , wherein the signal processor comprises:
 a correction filter adjusting a frequency dependency of at least one of the first and the second input signals into adjusted first or second input signals, respectively, and 
 a beamformer capable of combining the adjusted first and second input signals onto a beamformed signal with an adjustable directional dependency. 
 
     
     
       10. The hearing instrument according to  claim 9 , wherein the beamformer is an adaptive beamformer.